JEE Main 2021 (Online) 27th August Morning Shift | Dual Nature of Radiation Question 37 | Physics

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JEE Main 2021 (Online) 27th August Morning Shift

MCQ (Single Correct Answer)

-1

In a photoelectric experiment, increasing the intensity of incident light :

increases the number of photons incident and also increases the K.E. of the ejected electrons

increases the frequency of photons incident and increases the K.E. of the ejected electrons

increases the frequency of photons incident and the K.E. of the ejected electrons remains unchanged

increases the number of photons incident and the K.E. of the ejected electrons remains unchanged

JEE Main 2021 (Online) 26th August Evening Shift

MCQ (Single Correct Answer)

-1

The de-Broglie wavelength of a particle having kinetic energy E is $$\lambda$$. How much extra energy must be given to this particle so that the de-Broglie wavelength reduces to 75% of the initial value?

$${1 \over 9}$$E

$${7 \over 9}$$E

$${16 \over 9}$$E

JEE Main 2021 (Online) 26th August Morning Shift

MCQ (Single Correct Answer)

-1

In a photoelectric experiment ultraviolet light of wavelength 280 nm is used with lithium cathode having work function $$\phi$$ = 2.5 eV. If the wavelength of incident light is switched to 400 nm, find out the change in the stopping potential. (h = 6.63 $$\times$$ 10^$$-$$34 Js, c = 3 $$\times$$ 10⁸ ms^$$-$$1)

1.3 V

1.1 V

1.9 V

0.6 V

JEE Main 2021 (Online) 27th July Morning Shift

MCQ (Single Correct Answer)

-1

If 'f' denotes the ratio of the number of nuclei decayed (N_d) to the number of nuclei at t = 0 (N₀) then for a collection of radioactive nuclei, the rate of change of 'f' with respect to time is given as :

[$$\lambda$$ is the radioactive decay constant]

$$-$$ $$\lambda$$ (1 $$-$$ e^{$$-$$$$\lambda$$t})

$$\lambda$$ (1 $$-$$ e^{$$-$$$$\lambda$$t})

$$\lambda$$e^{$$-$$$$\lambda$$t}

$$-$$ $$\lambda$$e^{$$-$$$$\lambda$$t}

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